from rest_framework import serializers

from goods.models import SKU
class CartSerializer(serializers.Serializer):
    # 购物车的序列化器
    # 定义字段
    sku_id=serializers.IntegerField(label="商品 sku 编号",min_value=1)
    count=serializers.IntegerField(label="商品数量",min_value=1)
    selected=serializers.BooleanField(label="是否勾选",default=True)

    def validate(self, attrs):
        sku_id=attrs["sku_id"]
        count=attrs["count"]

        # 判断sku_id是否存在
        try:
            sku=SKU.objects.get(id=sku_id)
        except SKU.DoesNotExist:
            raise serializers.ValidationError("sku_id不存在")
        # 判断库存
        if count > sku.stock:
            raise serializers.ValidationError("库存不足")
        return attrs

class CartSKUSerializer(serializers.ModelSerializer):
    """
    购物车商品数据序列化器
    """
    count = serializers.IntegerField(label='数量')
    selected = serializers.BooleanField(label='是否勾选')

    class Meta:
        model = SKU
        fields = ('id', 'count', 'name', 'default_image_url', 'price', 'selected')

class CartDeleteSerializer(serializers.Serializer):
    """
    删除购物车数据序列化器
    """
    # 因为删除购物车数据不用获取商品的数量  所以在定义一个序列化器
    sku_id = serializers.IntegerField(label='商品id', min_value=1)

    def validate_sku_id(self, value):
        try:
            sku = SKU.objects.get(id=value)
        except SKU.DoesNotExist:
            raise serializers.ValidationError('商品不存在')

        return value
class CartSelectAllSerializer(serializers.Serializer):
    """
    购物车全选
    """
    selected = serializers.BooleanField(label='全选')
